[OpenIndiana-discuss] Linux software-raid with two Comstar iSCSI volumes

[Richard Elling]

On Nov 16, 2012, at 4:19 PM, Jim Klimov <jimklimov at cos.ru> wrote:

> On 2012-11-17 00:46, Roel_D wrote:
>> How about teaming? Is it supported under OI?
> 
> 
> My memory serves me not worse than google: teaming is one of the
> umbrella terms to describe what is implemented by LACP - a means
> of representing several hardware links as one logical NIC with
> increased reliability and bandwidth. Other vendors call (their
> proprietary implementations of) this technology as NIC bonding,
> EtherChannels, etc. In Solaris these are known as "aggregations"
> (see "dladm create-aggr ...").

LACP is link aggregation control protocol, which can be optionally used to 
help manage Ethernet link aggregations (IEEE 802.3ad, later 802.1AX).
The IEEE standard is for link aggregation, which is why they are named
aggregations in illumos/Solaris OSes.
http://en.wikipedia.org/wiki/Link_aggregation

> 
> BEWARE THAT sometimes the boost in bandwidth is not easy to see,
> because certain implementations switch connections between a
> couple of MAC addresses using one link, and only if you have
> lots of different hosts you get more bandwidth on the average -
> but a single GbE between a couple of nodes. This is likely a
> problem in the storage scenario, at least with one NAS server.
> 
> "Teaming" usually requires support on the switch side and while
> many managed switches provide LACP or a proprietary analog of
> this protocol across ports in one device, few allow spanning LACP
> domains over separate switches (as was touched on earlier in the
> thread).

"teaming" or "bonding" is simply confusing slang for link aggregation.
  -- richard
>